1. Field of the Invention
This invention relates generally to a lockbolt installation tool and more particularly concerns a portable tool which automatically feeds a lockbolt collar from a self-contained cartridge or magazine through a pivotable delivery tube to an installation position adjacent the tool nosepiece.
2. Description of Prior Developments
Abutting workpieces are commonly joined together with the use of pin and collar type fasteners known as lockbolts. The lockbolt pin is inserted through an opening in each workpiece so that the head of the pin contacts an exposed surface of one workpiece and the tail of the pin projects through the other workpiece. The collar is then fitted over the pintail and the fastener is set by axially pulling the pin with an installation tool and applying the reaction force to the collar.
The reaction force locks the collar to the pin by plastically deforming or swaging the collar into locking grooves formed in the pin. Details of this operation are set forth in U.S. Pat. No. 2,531,048, the specification of which is incorporated herein by reference. This assembly operation is labor intensive as the pin and collar are typically located by hand prior to setting.
To partially automate this process various arrangements have been designed to automatically feed the collar to an appropriate position within the installation tool so that the collar and tool may be simultaneously positioned around the pin to facilitate the swaging process. Although these automatic collar feeders present an improvement over a completely manual operation, several drawbacks have been associated with their use. The major drawback is the frequency with which these collar feeding mechanisms become jammed.
Conventional collar feeding mechanisms have used a flexible external hose for interconnecting a vibratory collar sorting bin or collar reservoir with a feed port on the body of the fastening tool. Collars have been found to jam at the interface between the tool body and the external hose due to the discontinuity in the collar feed path at this junction. Moreover, once a collar has passed through the feed port and entered the tool, various steps, transitions or other discontinuities in the feed path present additional obstacles to the travel of the collar and have also been a cause of jamming.
The use of an external feed hose presents additional installation problems. The flexible hose can become kinked resulting in a misfeed. Furthermore, a tool operator or co-worker can accidently step on the flexible hose thereby cutting off the supply of collars to the tool. In some cases the manipulation of the tool through awkward positions can cause the collar delivery hose to bind or kink. Because of the limited space within which some lockbolts are located, the feed tube can complicate or prevent tool access to the fastener by interfering with the workpiece or other structures adjacent the fastener installation site.
Accordingly, a need exists for an automated jam-resistant collar feed mechanism for a lockbolt installation tool which facilitates the placement of a collar over a pin, yet which allows easy access to all installation sites.